It's possible you might be thinking of a different character or a different story. Could you provide more context or details? Perhaps you're thinking of:
* A different character from Tex: There are many characters in the Tex series, including Tex Willer himself, his sidekick Kit Carson, the villain Mefisto, and various Native American tribes.
* A character from a different comic series: There are many characters in different Western comic series, some of which may have the name "Lem."
* A character from a different medium: Perhaps you are thinking of a character from a movie, TV show, or book that is not related to Tex.
Please provide more information so I can help you identify who "Lem" is.